Split from this thread:-
https://www.vintage-radio.net/forum/...php?t=172406:-
And while we are looking at the R209 Mk.I its worth saying a few things about its history, which I think is interesting - and with a certain amount of mystery reaching back into WWII.
Some think the set is one of the "Larkspur" radios, simply because it has a similar "look", with its cast alloy case which is hermetically sealed - a big feature of the Larkspur radios like the C11, R210, C42, etc. However it was in fact designed late in WWII, and was quickly partnered with the WS53 transmitter as a replacement for the earlier R107. It was thus a "model" for the later sets, and incorporated new ideas, such as modular construction, and FM as new and better mode than AM at HF.
What's even more interesting about it is the set that the R209 itself was based on. If you look closely at its case, you may note four holes in square on the top side. Apparently unused and redundant. Those were for an aerial base for the earlier set, the WS42, and the R209 re-used its cast alloy case.
The WS42 itself was an extremely advanced set for its time, incorporating not just FM to its AM and CW modes, but also a sort of "mechanical synthesiser" which allowed the operator to dial up the frequency wanted in 10kHz steps. It also managed an output on CW of 10 watts, which compared to other sets produced during WWII, WS19, WS22 WS62 etc was an astonishing advance in such a small portable package. And that's apart from its hermetic sealing, its cast alloy rigid case, which became a model for the much later Larkspur series.
The mystery arises as to why a set like the WS42 was suddenly designed during WWII with a radically different "design philosophy" from the run of the mill WWII radios. WftW reveals that it was designed by SRDE - the government signals research body. But as the wartime records for SRDE have all been lost I am not sure where that snippet of info came from.
I did an interview with Walter Farrar G3ESP (now long dead) where he told me he worked for SRDE during WWII, and specifically on FM at HF, and he had some amusing tales to tell! He also did the work on evaluating the German sets captured during WWII to see what could be learnt from them. He didn't mention the WS42 at the time, but the mere fact that someone was looking at German kit - which heavily incorporates modular design, alloy castings, and so on - and which looks something like the WS42 and R209 - suggests to me that this "step change" in design philosophy (as shown by the WS42) was initiated by an exposure of SRDE designers to German radio equipment.
All mere speculation of course, just putting 2 and 2 together.......
Richard